Collision-induced dissociation of the phenylsilane molecular ion.

The high-energy collision-induced dissociation of the phenylsilane molecular ion generated by electron ionization has been investigated using tandem mass spectrometry (MS/MS). It was observed that the dissociation of the molecular ion (M+.) occurs mainly via [MH]+, [M2H]+., and [M3H]+, followed by two consecutive losses of C2H2. The structures of the precursors for the [MCH3]+, [MSiH]+, and [MSiH2]+. ions are proposed. The data suggest that the molecular ion undergoes rearrangements to several isomers prior to dissociation, including the ion containing a five-membered carbon ring. Reaction mechanisms are proposed for the dissociations via the isomeric molecular ions. Copyright © 2002 John Wiley & Sons, Ltd.